The Rams and the St. Louis Convention and Visitors Commission are hundreds of millions of dollars apart on their proposals to build a new stadium, replacing the 18-year-old Edward Jones Dome.

A contract with the Rams says an upgrade to the Dome is required to keep the team playing in St. Louis after the 2014-2015 season. The Dome must be upgraded to a first-tier stadium, which means ranking in the top 25 percent of NFL stadiums. The team is free to walk in 2015 if an agreement is not made between the Rams and the CVC.

The Rams could also go year-to-year on their lease if they want to continue negotiating a deal.